1. Field of the Invention
The present invention relates to a Group III nitride compound semiconductor device. For example, the invention is adapted for improvement of a p-type layer in a Group III nitride compound semiconductor device such an a blue light-emitting diode.
2. Description of the Related Art
A Group III nitride compound semiconductor device having a p-type layer of a multi-layered structure has been heretofore proposed. For example, a p-type layer of a superlattice structure constituted by an alternate laminate of AlGaN and GaN has been disclosed in K. Kumakura and N. Kobayashi; Jpn J Appl. Phys. 38(1999) L1012.
When the p-type layer wag formed to have a superlattice structure in this manner, the electric resistance of the p-type layer itself was reduced. Greater improvement in electrical characteristic of the p-type layer has been, however, required of recent devices.